Bifunctional Phosphine Ligand Enabled Gold‐Catalyzed Alkynamide Cycloisomerization: Access to Electron‐Rich 2‐Aminofurans and Their Diels–Alder Adducts. (15th October 2019)

• Record Type: Journal Article
• Authors: Li, Xingguang; Ma, Xu; Wang, Zhixun; Liu, Pei‐Nian; Zhang, Liming
• Is Part Of: Angewandte Chemie. Volume 131:Number 48(2019)
• Page Start: 17340
• Page End: 17344
• Publication Date: 2019-10-15
• Subjects: Diene -- Diels-Alder-Reaktionen -- Gold -- Heterocyclen -- Isomerisierungen; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201908598
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: By using biphenyl‐2‐ylphosphines functionalized with a remote tertiary amino group as a ligand, readily available acetylenic amides are directly converted into 2‐aminofurans devoid of any electron‐withdrawing and hence deactivating/stabilizing substituents. These highly electron‐rich furans have rarely been prepared, let alone applied in synthesis, because of their high reactivities and low stabilities associated with the electron‐rich nature of the furan ring. In this work, these reactive furans smoothly undergo either in situ intermolecular Diels–Alder reactions to deliver highly functionalized/substituted aniline products or intramolecular ones to furnish carbazole‐4‐carboxylates in mostly good to excellent yields. This work offers general and expedient access to this class of little studies electron‐rich furans and should lead to exciting opportunities for their applications. Abstract : Ein wahrer Goldschatz : Mit difunktionellen Liganden, die spezifisch für die Goldkatalyse entworfen wurden, lassen sich acetylenische Amide in einem Schritt in 2‐Aminofurane überführen. Diese Furane sind auf andere Weise wegen ihrer elektronenreichen Natur schwer zugänglich, zugleich jedoch von außergewöhnlichem Synthesewert.